Traditional batch style of manufacturing calls for large batches of workpieces to be processed at each of a plurality of work stations. At each work station, a large batch of workpieces is processed, and when all of the workpieces in the batch are completed, the batch is transported to the next work station, where a different work operation is performed on each of the workpieces in the batch, and so on, until the batch has moved through all of the work stations on the manufacturing line. Efficiency and productivity studies have shown that in some applications this batch style of manufacturing is inefficient, and that significant improvements in efficiency and productivity can be attained by instead using a single-part-flow style of manufacturing.
In the single-part-flow manufacturing line, a number of work stations are arranged in close proximity to each other so that an operator can easily access each work station with minimal walking or movement required to get from one work station to the next. For example, a number of different machines can be arranged in a U-shaped cell with the operator in the middle. One such manufacturing method is sometimes referred to as a Chaku Chaku type of process. "Chaku Chaku" is a Japanese terms that means "load load." In a Chaku Chaku line, the machines are typically designed such that the operator can load a workpiece into a machine and turn the machine on so that the machine begins its process, and the machine will automatically complete its process without further intervention of the operator. The operator picks up the completed workpiece processed by a given machine, loads a new workpiece into that machine, and starts the machine. The operator then takes the completed workpiece, loads it into the next machine in the line, picks up the previously completed workpiece from that machine, and starts the machine. The process continues down the line. Thus, a given workpiece flows from machine to machine in a very synchronized manner, and does not have to traverse a great distance during the process.
To facilitate this Chaku Chaku style of manufacturing, it should be apparent that it is desirable for a given machine in the line to be automatically operable to as great an extent as possible. It should be relatively easy for the operator to remove a completed workpiece from the machine and to load a new workpiece into the machine. The loading and removal process are performed manually by the operator in many such machines, thus requiring the operator to place his or her hands near moving parts of the machine. Thus, while accessibility to the machine by the operator is essential, safety must also be a key consideration in the design of the machine. Conventional brake presses used for bending sheet metal often require the operator to place his or her hands near the moving press tooling during press operation, thereby compromising safety.